Output Parameter of Stored Procedure is not getting set - sql-server

Question

So I have the following stored procedure:
CREATE PROCEDURE dbo.uspUpdateOrInsertDataObjectValue
#ParentDataObjectId INT,
#DataObjectName NVARCHAR(256),
#DataObjectValue NVARCHAR(256),
#ForceInsert BIT,
#ReturnDataObjectId INT OUT
WITH RECOMPILE
AS
BEGIN
if #ForceInsert = 0
BEGIN
UPDATE DataObjects SET Value=#DataObjectValue WHERE Name=#DataObjectName AND ParentDataObjectId=#ParentDataObjectId
END
if ( #ForceInsert = 1 ) OR ( ##ROWCOUNT = 0 )
BEGIN
--Spend time on the hierarchy id stuff only if we have to insert
DECLARE #ParentTreeId HierarchyId
DECLARE #LastChildTreeId HierarchyId
SELECT #ParentTreeId = TreeId FROM DataObjects WHERE DataObjectId=#ParentDataObjectId
SELECT #LastChildTreeId = MAX(TreeId) FROM DataObjects WHERE TreeId.GetAncestor(1)=#ParentTreeId
INSERT INTO DataObjects ( Name, Value, ParentDataObjectId, TreeId ) VALUES ( #DataObjectName, #DataObjectValue, #ParentDataObjectId, #ParentTreeId.GetDescendant( #LastChildTreeId, NULL ) )
END
SELECT #ReturnDataObjectId = (SELECT TOP 1 DataObjectId FROM DataObjects WHERE Name=#DataObjectName AND ParentDataObjectId=#ParentDataObjectId ORDER BY DataObjectId DESC)
RETURN 0
END
GO
`
And I'm executing it like this:
int iParentDataObjectId = 1;
int iDataObjectId = 0;
SQLWCHAR name[256];
SQLWCHAR value[256];
_sntprintf_s( (wchar_t*)name, 256, _TRUNCATE, _T("%s"), pCDBDataObject->GetName() );
_sntprintf_s( (wchar_t*)value, 256, _TRUNCATE, _T("%s"), pCDBDataObject->GetString() );
result = SQLBindParameter( sqlStatementHandle, 1, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &iParentDataObjectId, 0, NULL );
result = SQLBindParameter( sqlStatementHandle, 2, SQL_PARAM_INPUT, SQL_C_WCHAR, SQL_WVARCHAR, 256, 0, name, 256, NULL );
result = SQLBindParameter( sqlStatementHandle, 3, SQL_PARAM_INPUT, SQL_C_WCHAR, SQL_WVARCHAR, 256, 0, value, 256, NULL );
result = SQLBindParameter( sqlStatementHandle, 4, SQL_PARAM_INPUT, SQL_C_BIT, SQL_BIT, 1, 0, &forceInsert, 0, NULL );
result = SQLBindParameter( sqlStatementHandle, 5, SQL_PARAM_OUTPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &iDataObjectId, 0, NULL );
result = SQLExecDirect( sqlStatementHandle, (SQLWCHAR*)_T("{CALL uspUpdateOrInsertDataObjectValue (?,?,?,?,?)}"), SQL_NTS );
'
The stored procedure executes properly and inserts or updates the database but iDataObjectId never changes.
However when I execute it like this in a script in Sql Server Management Studio:
DECLARE #testval int
EXECUTE uspUpdateOrInsertDataObjectValue 1, 'Config', 'testasdfasdfasdfas', 1, #testval OUT
SELECT * from DataObjects where DataObjectId=#testval
the output value is assigned to #testval and the subsequent select statement works just fine.
What am I missing?

Answer 1

I found the answer after a more careful examination of this example: http://technet.microsoft.com/en-us/library/ms403283.aspx
You need to clean out the result sets of the query(call) with SqlMoreResults before the output variables get set. Not the behavior I would have expected but it was right there in the documentation.